U.S. Pat. No. 4,086,829 discloses a ratchet wrench having a handle which may be turned about its own axis to rotate the transversely-directed head of the wrench, as long as the resistance to head rotation is below a preselected torque load level, to tighten or loosen a nut or other workpiece. The wrench thus has two operating modes: a first mode in which rotation is imparted to the head by turning the handle about its longitudinal axis, and a second mode in which rotation is imparted to the head by oscillating the handle back and forth in a conventional ratchet wrenching operation. The two modes are non-interfering so that, for example, during the ratcheting operation there will be insufficient feedback to cause the handle to twist in the user's hand.
This invention is concerned with a wrench which has the dual operating modes of the wrench of U.S. Pat. No. 4,086,829 but which has important structural differences which yield improved clutch action, increased handle strength, reduced exposure to damage, increased protection against contact by fluids that might adversely affect wrench operation, and significantly lower manufacturing costs.
The improved wrench of this invention has a single-piece handle which is solid throughout substantially its entire length, thereby yielding greater strength and reduced manufacturing costs in comparison with a centrally-bored handle of machined, two-piece construction. The clutch mechanism is disposed within and protected by the head housing, along with other components of the wrench's operating mechanism. Since the handle is formed in one piece and requires no machining or drilling in production, it may be drop-forged for even greater strength and dependability.
In brief, the ratchet wrench includes an elongated handle with a head assembly at one end of that handle, the head assembly comprising a head housing rotatably receiving the end of the handle, a drive member carried by the housing for rotation about an axis transverse to the axis of the handle, and a ratchet-equipped coupling assembly operatively joining the drive member and housing for rotation of the drive member one way or the other about the transverse axis in response to oscillation of the handle. Within the head housing is a clutch assembly which couples the handle and the drive member for simultaneous rotation about their respective axes only below a preselected torque load level. Specifically, the clutch assembly includes a clutch sleeve and a clutch body interposed between and operatively connected to the handle and the drive member, respectively, the sleeve being slidable relative to the clutch body when the preselected torque load level is exceeded. In the disclosed embodiment, the sleeve is provided at opposite ends with a pair of inwardly tapering frusto-conical clutch surfaces and the clutch body takes the form of a clutch nut and a clutch gear having frusto-conical outer surface portions received in the ends of the sleeve and frictionally engaging the tapered surfaces of that sleeve. Adjustable connecting means extend through the sleeve to join the clutch nut and clutch gear for limited axial adjustment while at the same time securing such parts against independent relative rotation. The torque load level may therefore be varied by adjusting the connecting means and the force with which the conical surfaces of the clutch nut and clutch gear engage the sleeve. The sleeve is in turn formed of a tough, durable, but slightly deformable material, such as nylon or other polymeric material having similar characteristics, so that the outward forces exerted upon the sleeve by the clutch nut and clutch gear will cause the sleeve's outer surface to tightly engage the inner surface of the cavity of the handle in which the clutch assembly is located. The adjustable connecting means therefore performs the dual functions of setting the torque load limit of the clutch and locking the sleeve against rotation relative to the handle.
Other features, objects, and advantages will become apparent from the specification and drawings.